1. Field of the Invention
The present invention relates to a speaker identifying technique for identifying or authenticating (hereinafter simply referred to as “identify”) a speaker based on the voice of the speaker. More specifically, the present invention relates to a speaker identifying apparatus identifying, among a plurality of candidates, one having the highest probability as the speaker.
2. Description of the Background Art
In these days, as information comes to mean more and more in our social life, increasing number of problems arise in relation to the information, including information theft and wrongful use of portable telephones. In order to tackle such problems, a technique of determining whether a user is authenticated or not, or who is the user, that is, an individual identifying technique is desired for application to computers, automated teller machines of banks, portable telephones and the like.
Recent techniques for determining whether a user is authenticated or not often utilize biometrics information, typically including fingerprints, vein distribution on a palm, or iris patterns. Such information differs person to person, and is effective enough to deter “spoofing”.
Individual identification using such information, however, often requires dedicated hardware, leading to undesirably expensive system.
Speech information is a kind of biometrics information. Speech information has been conventionally used for identifying an individual. Speech reflects geometrical features of one's speech organ, and therefore, it is considered suitable for individual identification.
As a prior art technique using speech, Japanese Patent Laying-Open No. 2004-258845 discloses a sound spectrogram authentication system that identifies an individual using information of sound spectrogram. According to the sound spectrogram authentication system, sound spectrogram of a user is pre-stored (enrolled) and, at the time of authentication, sound spectrogram of the speech as an input is collated with the enrolled sound spectrogram to determine whether the user should be authenticated or not. Here, the sound spectrogram authentication may be regarded as a technique for identifying an individual using the sound spectrogram.